The present inventions relates to a fan and in particular to a fan with a magnetic member.
A conventional fan is shown in FIG. 1, including a rotor 1, a stator 2 and a frame 3. The rotor 1 connects the stator 2 by a C-ring 4, keeping the stasis of the rotor 1 and the stator 2.
After assembly, the center of the magnet belt 13 in the rotor 1 and the center of a coil 22 in the stator 2 are at the same height. Namely, the magnetic center A of the magnet belt 13 and the magnetic center B of the coil 22 are positioned in line. When the rotor 1 rotates, airflow produces an elevating force on the rotor 1, a shaft 15 of which then shifts up and down. Thus, the fan generates noise, and the C-ring 4 and other elements can be damaged by the vibration.
One conventional method to solve the problem mentioned is shown in FIG. 2, in which the magnetic center A of the magnet belt 13 is positioned higher than the magnetic center B of the coil 22. Namely, the center of the magnet belt 13 is higher than the center of the coil 22. When the electrical field surrounding the coil 22 rotates the rotor 1, magnetic attraction is generated on the magnet belt 13 of the rotor 1 and pulls the rotor 1 down, reducing elevating force on the rotor 1.
This method cannot, however, be used with fans having different speeds, high speeds, or reverse assembly. The attracting force is not strong enough to attract and secure the rotor 1, decreasing heat-dissipation efficiency. Further, some rotational force of the rotor 1 is converted to elevating force, decreasing speed.